start =
  element library {
    element book {
      element isbn { xsd:token }
      & attribute id { xsd:token }
      & attribute available { xsd:boolean }
      & element author {
          attribute id { xsd:token }
          & element name { xsd:token }
          & element born { xsd:date }
          & element dead { xsd:date }
        }*
      & element character {
          attribute id { xsd:token }
          & element name { xsd:token }
          & element born { xsd:date }
          & element qualification { xsd:token }
        }*
      & element title {
          attribute xml:lang { xsd:language },
          xsd:token
        }
    }*
  }
